Top 30 Programming Interview Questions and Answers in 2023

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Programming questions are a crucial aspect of a developer position interview. Knowledge of fundamental programming ideas is always expected regardless of the programming language you are proficient in. Therefore, coding abilities are always decisive in programming interviews. In this article on Programming interview questions, we will cover the top 30 questions you must know to ace interviews and land your dream job.

1. Which Programming Languages Do You Have Previous Experience Working With?

I have expert Java, C++, JavaScript, C#, Ruby, and Python knowledge. Java, C#, and C++ are the programming languages with which I feel most comfortable working. In my previous position, I utilized Java extensively to develop cross-platform applications. Using C++, I also created a new operating system compatible with my designed applications. Using C#, I could develop web applications and software more efficiently.

2. What Part Of Our Company, Product, Or Team Are You Most Interested In?

I watched an interview with your company’s chief executive officer in which he discussed your disruptive lending product. The potential for streamlining strenuous activities such as loan applications is enormous. I believe that the expansion of this industry over the past year is a significant indicator of the future. In addition, I am delighted by the unrealized potential of the blockchain technology you have opted to implement. I see this as a competitive advantage for your organization in this industry since verified auditability will lower compliance expenses.

3. Are You Comfortable Working Under Strict Time Constraints?

Yes, I am comfortable working under strict time constraints. Throughout my career as a programmer, I have been required to meet strict deadlines for numerous projects. I once led a team of programmers to complete a two-month project, for instance. To ensure the project’s success, I had to delegate tasks to other team members so that we could all work together to meet the deadline.

4. What Are The Essential Qualities A Programmer Should Possess?

A variety of skills and knowledge are required to be a successful programmer. Experience, adaptability, and originality are necessary for success in this field. However, the true test of a programmer’s skills and strengths is based on certain personality traits and cognitive abilities. The ability to think quickly and solve problems without delay is valued more than a candidate’s number of certifications or years of work experience. Here are five qualities of a successful programmer essential for success in this field.

5. What Type Of Programming Would You Focus On Initially If Hired?

Through my programming, I am passionate about creating unique experiences for audiences. I believe that a successful event leaves attendees inspired or amused. If hired, my priority would be to develop more diverse programming options. For instance, I want to create more events featuring local musicians and comedians. I also wish to increase the number of monthly family-friendly events.

6. How Well Do You Work When There Is A Lot Of Pressure On You?

I am accustomed to working under pressure, as I have done so for years. One night at my previous job, we had a very tight deadline. I had to improvise a new plan on the spot because we lacked crucial elements for our performance. First, I assembled the group and explained the situation. Then, we collectively came up with ideas for how to proceed. Following a discussion of several options, we settled on a solution.

7. What Distinguishes You From Other Candidates?

Compared to other candidates, my ability to collaborate with a diverse range of individuals is most likely what distinguishes me. I can successfully manage a diverse range of personalities and points of view because I have worked in large and small organizations. Furthermore, I find it beneficial to solicit input from everyone on staff when making programming decisions. It allows me to create a schedule that appeals to the greatest number of viewers possible.

8. Please Describe Your Most Recent Project, Including Any Obstacles Encountered And Your Contributions To Its Success.

A former employer tasked me with developing an online learning and training program for internal employees. The program was designed to ensure that all employees received proper training on certain topics, including customer service, legal compliance, and workplace ethics. I began by researching similar training systems to determine which ones worked and which did not. Next, I coded a simple program in Java, which I used to upload training courses. After testing the simplified program, I added interactive games and quizzes to make it more engaging for employees. Employees of the organization reacted positively to this program, and their customer service success rates increased by 25% after all team members completed the required training.

9. Tell Me About Your Experience Working In A Programming Position.

I graduated from a local university in 2016 with a degree in software development. I immediately began an internship at a software firm. During my year there, I learned how to develop software professionally and gained experience communicating with clients and estimating projects. After that, I began working as a junior developer for a Software Company. A year into that position, I was promoted to senior developer, which entailed managing my projects and vetting those of junior developers before delivery to the client. I held that role until the company fell last month.

10. What Is Your Greatest Weakness As A Programmer?

I tend to spend too much time on some activities and not leave enough for others, so I made a calendar where I can block out when I’ll work on which project. I set timers to go off in the middle, and after each block so I know when to begin tying it up. Then, if I need to, I can always go back and spend extra time on something, but this way, I don’t miss any little things that need to get done that day.

11. Describe Computer Programming In Detail.

Computer programming is the process of composing computer instructions in the form of code. Developers write the code in a programming language, which is then translated into a computer-understandable notation so that the computer can perform some tasks. A program is a collection of logical, mathematical, and sequential operations. When grouped, these functions accomplish a task. Each programming language focuses on distinct types of tasks and issues commands to the computer in a unique manner.

12. What Is The Definition Of Object-Oriented Programming?

Object-oriented programming is a programming paradigm founded on the idea of objects. These objects may include data and code run to manipulate the data. Objects may also be provided to functions as arguments or returned from functions, allowing for a significant deal of flexibility and code reuse.

13. What Exactly Is A Data Structure?

Data structures are a specific method of organizing data in a specialized format on a computer, allowing the data to be efficiently structured, processed, stored, and retrieved. In addition, they are a method for managing information, rendering the data usable.

Every application, piece of software, and program’s core consists of two elements: algorithms and data. Information is data, and algorithms are the rules and instructions that transform data into something useful for programming.

14. Can You List And Describe The Different Types Of Errors That Can Occur During The Execution Of A Computer Program?

During the execution of a computer program, the following errors may occur: 

  • Errors in logic occur when a computer program implements incorrect logic. The absence of a report for these programming errors is the most challenging to address.
  • Errors that occur at runtime occur when a program contains an illegal operation. For instance, dividing a number by zero. These are the only errors displayed immediately during the program’s execution. When a runtime error occurs, execution of the program is halted, and a diagnostic message is displayed.
  • Syntax errors – occur when one or more of the grammatical rules of the programming language being used are broken. Such errors are detected at the time of compilation.

15. Describe A Significant Application Bug You Had To Fix. How Did You Troubleshoot?

Our DevOps team reported that a costly UI query was stressing one of our databases. I checked the logs to see when the problem began. It showed me the bug’s commit range. Unfortunately, I could only reproduce the newest bug in production. Next, I used git bisect to find the bug-causing commit and withdrew the branch. Again, I couldn’t replicate the problem. Next, I used browser devtools on the UI. Our production environment doesn’t have source maps; therefore, I had to map minified JavaScript to CoffeeScript.

I found that the harmful method was called on every page, not only occasionally by a feature. I found no modification to the method in the commit I’d identified before. The only modification I found was an unrelated alteration to a file line that had been “commented out” three years earlier. I deployed some separate logging statements to verify the procedure. 

16. What Concepts Are Introduced By Oops?

The following principles are introduced in OOPs:

  • Object – A physical entity with a specific state and behavior. We can declare it as a class instance.
  • Class – A logical entity specifies the blueprint from which an object can be instantiated or generated.
  • Inheritance is the process by which an object acquires the attributes and behaviors of its parent object. It allows for code reuse.
  • Polymorphism is a notion that permits a task to be executed in multiple ways. Method overloading and method overriding are used to achieve polymorphism in Java.
  • Abstraction – It is a notion that conceals the inner workings of an application and reveals only its usefulness. Abstraction is achieved using abstract class and interface in Java.
  • Encapsulation is the practice of combining code and data into a single entity.

17. Describe The Idea Of Loops In More Detail.

A loop is a series of instructions that are repeated until a particular condition is met. In a loop structure, the loop asks a query (e.g., has the value of the variable X reached 5?). If the response is negative, an action is performed. The question is repeatedly posed until no further action is necessary. A loop protects programmers from repeatedly writing the same piece of code.

18. Reserved Words Exist In Every Programming Language. What Exactly Are They? Give Some Examples.

Reserved words, also known as keywords, are programming language-specific words with predefined meanings. These reserved words cannot be used for other purposes or redefined. Here are several examples of reserved words:

  • For example, C consists of break, case, char, default, float, and if.
  • The Java keywords are abstract, boolean, catch, class, const, double, enum, implements, instance, throws, transient, and volatile.
  • Python includes asserting, continue, def, del, global, not, lambda, and yield.

19. Please Describe The Program Documentation. Why Is It Significant?

Program documentation describes a computer program’s algorithm(s), coding method, design, testing, and proper use. It is beneficial for those who use the program daily and the programmer(s) tasked with correcting, modifying, and updating the computer program.

A committed programmer must have access to trustworthy documentation. The availability of comprehensive documentation aids in keeping track of the various aspects of a computer application and enhancing the application’s overall quality. However, program documentation primarily concerns the development, maintenance, and knowledge transfer to other developers.

20. Please Describe The Available Operator Types.

Operators are used in computer programs to perform specific operations on data. These are denoted with symbols. For instance, / represents the division in mathematics while * represents multiplication. There are four major categories of operators:

  • Arithmetic – Capable of performing mathematical operations
  • Assignment – Used to store results of computations, strings, and values in variables.
  • Logical – Allows a computer program to decide based on multiple conditions. In other words, logical operators enable the combination of simple conditions to create more complex ones.
  • Relational – Used to define or test a relationship between two entities. These operators evaluate to either true or false and generate a value greater than zero.

21. Explain The Difference Between Low-Level And High-Level Programming Languages. Also, Provide Examples.

Low-level programming languages are those that offer no generalization from the instruction set architecture of the computer. Typical examples of low-level programming languages include assembly language and machine language.

A high-level programming language provides high generalization from the instruction set architecture of a computer. High-level programming languages typically contain elements that resemble natural language to facilitate program development. An additional definition of a high-level programming language is independent of the system’s underlying processor. C++, Java, and Python are popular high-level programming languages.

22. How Do You Explain Technological Difficulties To Stakeholders Without Technical Backgrounds Or Knowledge?

When facing a barrier, I do not believe it is my responsibility to change the project’s scope alone. In many cases, the quality of the software is determined by balancing scope, cost, and time. This equilibrium is a business decision, not a technological one. Instead, I propose viable alternatives and describe their effect on the equilibrium. For instance, if an obstruction threatens to considerably extend the delivery date beyond what was anticipated, I may propose a solution that can meet the current deadline. In comparison, maintaining the majority of the original scope but at the expense of quality and user experience.

Or, I can advise decreasing the priority of specific features linked to the roadblock so we can deliver a portion of the original feature set inside the scheduled delivery window. But, again, it is typically where a conversation begins, as stakeholders inquire further about what can and cannot be done. But, again, this collaborative procedure guarantees that all parties are comfortable with the final choice.

23. Explain Machine Code In Your Own Words.

The term “machine code” can be used to refer to any low-level programming language that is composed of machine language instructions. It might be written in hexadecimal or binary, but visually it looks like a long string of ones and zeros. Because it is time-consuming and prone to making mistakes, the majority of computer programs are not written in machine code. Writing in machine code, on the other hand, might be necessary for low-level debugging, program patching, or when disassembling assembly language.

24. What Are Your Thoughts On Doubly Linked Lists?

Doubly linked lists are a subtype of linked lists in which traversal of the data components can occur in both directions. It is made feasible by the availability of two links in each node. One connects to the node immediately adjacent to it, and another connects to the node immediately preceding it.

25. What Exactly Is “Agile” Software Development, And How Do You Feel About It?

Agile software development is a methodology that emphasizes incremental delivery by the entire team. Therefore, the project is divided into “sprints” that are done before the deadline. In my prior position, we were fairly effective at adopting the process. We utilized two-week sprints and frequent face-to-face meetings to address problems and concerns as they occurred.

Moreover, we had regular standup sessions to keep everyone apprised of team progress. The one change I would have made to the procedure concerned our standup meetings. “standup” refers to meetings held while standing to enhance concentration and brevity. Our sessions, however, tended to morph into formal status meetings for our team leader rather than staying a time for our team to sync. The process did, however, assist in delivering higher-quality software on a more predictable schedule.

26. How Does The Declaration Of Variables Influence Memory?

The data type stored in that variable will determine the amount of memory that needs to be reserved or allocated for that variable. For example, for illustration’s sake, if a variable is declared to be of “integer type,” then 32 bits of memory storage will be set aside for that specific variable.

27. What Are Your Most Frequently Used Design Patterns, And In What Circumstances Do You Employ Them?

My level state and the player character are typically implemented as singletons in gaming projects. I’ll use a factory that produces unique enemies based on inputs for enemy creation. In addition, the character’s projectiles will be stored in an object pool to avoid performance issues caused by excessive instantiation and garbage collection. If the game becomes more complex, I may switch to a compositional model such as Entity-Component-System. The system functions would then employ dependency injection to improve the separation of concerns and the testability of the game logic.

28. Which Algorithm For Sorting Is The Best?

There are numerous sorting algorithms, including bubble sort, fast sort, balloon sort, merge sort and radix sort. However, no algorithm may be deemed the best or quickest because each was built for a certain sort of data structure in which it performs optimally.

29. What Do You Think About Software Testing?

Testing is crucial for developing high-quality software for our customers. In a new project, I will typically not lead with them. Instead, I view tests as a method for securing mature functionality. The project concept frequently diverges substantially from the final solution as we collect usage analytics and user input. I shall thus begin with simple manual testing. As soon as the feature set is stable, I will begin implementing tests. Most of my test suites will consist of unit tests focusing on essential application components.

In addition, I will have a limited number of integration tests utilizing Selenium. To guarantee that the execution time is not unreasonable, I will concentrate these tests on the most important user interactions. Lastly, providing the infrastructure provided by the DevOps team enables it, a canary deployment will be utilized for each release to minimize the effect of any missed bugs.

30. What Are Your Thoughts On Declarative Versus Imperative Programming Paradigms Like Functional And Object-Oriented?

We were tasked with reworking the browser client application for a particular project. It utilized an imperative, object-oriented methodology, with many custom controls deriving most of their functionality from an expanding inheritance hierarchy. We utilized this as an opportunity to adopt a more declarative strategy. As a result of no longer manually updating the interface in response to events, the number of state-related bugs decreased drastically after the conversion. It was formerly the most frequent type of user-reported bug.

Nevertheless, we had to make adjustments in a few key areas. In more dynamic and performance-sensitive portions of the application, the caching mechanisms we implemented to prevent excessive recalculation had grown excessively complex. We streamlined this by reverting to an imperative method for updating the component.


Now that you are familiar with the top 30 programming interview questions, you should look for opportunities to acquire the skills necessary. And capitalize on the immense popularity of software development and make a successful career in the field. So prepare for your upcoming interview with these questions to ace it and land your ideal job.